Rotary regenerator for a gas turbine engine with resilient mounts for positioning the regenerator

ABSTRACT

A rotary regenerator for use in a gas turbine engine comprising a ceramic core matrix and a circular rim surrounding the matrix as the regenerator rotates about its geometric axis, a ring gear carried by the rim for driving the regenerator, a resilient connection between the rim and the ring gear to establish a cushion for the ceramic core and means for resiliently mounting and positioning the regenerator core to establish proper sealing contact between the regenerator core and the regenerator seals as the latter sealingly engage the surface of the regenerator core.

tates atet 11 1 ROTARY REGENERATOR FOR A GAS TURBINE ENGINE WITI-llRESILIENT MOUNTS FOR POSITIONING THE REGENERATOR Inventor: V. DurgaNageswar Rao,

Woodhaven, Mich.

Assignee: Ford Motor Company, Dearborn,

Mich.

Filed: Nov. 19, 1973 Appl. No.: 417,441

US. Cl 165/8, 165/10, 74/443, 74/446, 64/27 NM Int. Cl. F2801 19/00Field of Search 165/8, 10; 74/446, 443; 1 64/27 NM References CitedUNITED STATES PATENTS Chute 165/8 X Nov. 19, 1974 3,300,967 1/1967Trapp 1. 165/8 x 3,789,917 2/1974 Jarry 165/8 FOREIGN PATENTS ORAPPLICATIONS 1,206,246 9/1970 Great Britain 1. 165/8 PrimaryExaminerAlbert W. Davis, Jr. Attorney, Agent, or Firm-Donald J.Harrington; Keith L. Zerschling [5 7] ABSTRACT A rotary regenerator foruse in a gas turbine engine comprising a ceramic core matrix and acircular rim surrounding the matrix as the regenerator rotates about itsgeometric axis, a ring gear carried by the rim for driving theregenerator, a resilient connection between the rim and the ring gear toestablish a cushion for the ceramic core and means for resilientlymounting and positioning the regenerator core to establish propersealing contact between the regenerator core and the regenerator sealsas the latter sealingly engage the surface of the regenerator core.

12 Claims, 17 Drawing Figures PATENIE WIQIBM 3,848,663

sum 20! e PATENTEL, rm 1 9 m4 saw u or a rm 1 91914 v SHEET 5 OF 6PATENTLU [Ill Ill! ROTARY REGENERATOR FOR A GAS TURBINE ENGINE WITHRESILIENT MOUNTS FOR POSITIONING THE REGENERATOR GENERAL DESCRIPTION OFTHE INVENTION This invention relates generally to rotary regeneratorsfor use in gas turbine engines. Examples of rotary regenerators that arecapable of embodying the improvement of my invention are shown in priorart US. Pat. Nos. 3,586,096, 3,496,933 and 3,525,384. Each of theseprior art patents is owned by the assignee of this invention.

A regenerator in a gas turbine engine of the type disclosed in theaforesaid patents and in this disclosure is situated typically in aregenerator core chamber in the engine housing and is covered by aregenerator cover. The engine housing and the regenerator core chamberdefine gas flow passages which are intersected by the regenerator core.Compressed air from the gas turbine engine compressor passes through onegas passage and combustion gases on the downstream side of the enginepower turbine pass through another passage. The core becomes heated bythe turbine exhaust gases and heated core region, upon rotation of theregenerator, comes in contact with the relatively cool compressed intakeair on the upstream side of the burner as the intake air passes througha different segment of the regenerator core. Gas seals capable ofwithstanding the operating temperatures encountered in the gas turbineengine are effective to seal and isolate one regenerator region at oneoperating pressure from another region at a different operatingpressure. The seals are situated on the opposite sides of theregenerator core in sealing engagement with the core surfaces as thecore revolves about its geometric axis. The regenerator core is drivenby a pinion which meshes with the ring gear mounted on the rim of theceramic regenerator core. One seal assembly is mounted on a seal surfaceformed on the engine housing adjacent one surface of the regeneratorcore and the other seal is mounted on the corresponding surface of theregenerator cover.

The seal assemblies are comprised of a seal diaphragm that is loadedwith the forces due to the differential gas pressures passing throughthe regenerator. The regenerator chamber defined by the engine housingand the regenerator cover has dimensions that are fixed, and theclearance for the regenerator seals therefore is fixed. The axis ofrotation and the clearance for the seals are controlled by balancing thegas loads on the diaphragm seal elements. It is desirable to balance thegas loading as much as possible so that the loads on the seal elementsare maintained at optimum levels and are distributed uniformly over theseal surface.

The improvements of my invention make it possible to achieve a betterbalance for the sealing forces. This results in a reduced seal wear rateand excessive local loads on the seal are avoided. The axis of rotationof the regenerator core is fixed thereby avoiding variations in the sealloads as the regenerator core rotates. Failure of the diaphragm sealelements after continued operation of the regenerator core are reducedin frequency.

The ring gear is mounted on the regenerator rim by a resilientattachment ring thereby providing a cushion which maintains theregenerator core in a fixed axial position and distributes seal loadsmore uniformly. It also avoids excessive localized loading due tomisalignment of the regenerator. The resilient connection also providesa damping action for the regenerator which prevents shock loading of theceramic core.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWING FIG. 1 shows anadjustable resilient mounting means for a rotary regenerator in a gasturbine engine.

FIG. 2 is a view similar to FIG. 1 showing an alternate mounting meansfor a regenerator having a split ring gear.

FIG. 3 is a view similar to FIG. 1 showing a second alternateconstruction of the resilient mounting means for a regenerator with asplit ring gear.

FIG. 4 is a view of an alternate regenerator mounting for a regeneratorrim similar to the rim shown in FIG. 1.

FIG. 5. shows a detail of a mounting spring used to establish ayieldable driving connection between a regenerator ring gear and aregenerator core rim.

FIGS. 6 and 6A show, respectively, the locking grooves in either end ofthe mounting spring shown in FIG. 5. I

FIG. 7 shows the mounting spring ends of FIGS. 6 and 6A together withthe locking element that joins the two ends together. 7

FIG. 8 is a plan view of the connection shown in FIG. 7.

FIG. 9 is a partial assembly view showing the mounting spring of FIG. 5assembled between the ring gear and the regenerator core rim.

FIG. 10 is a view similar to FIG. 9 showing a ring gear, a drive flangeand ring clip on the mounting spring.

FIG. 11 is a view similar to FIG. 5, but which includes also anillustration of resilient cushions between the regenerator rim and therim contacting forces of the mounting spring.

FIG. 12 is a cross sectional view taken along the plane of section line12l2 of FIG. 11.

FIG. 13 is a cross sectional view taken along the plane of section linel313 of FIG. 11.

FIGS. 14 and 15 show two other embodiments similar to the embodiment ofFIGS. 11 through 13.

PARTICULAR DESCRIPTION OF THE INVENTION In FIG. 1, reference character10 designates a ceramic regenerator core with asteel rim 12. A ring gearmounting material, preferably made of a high temperature elastomer, issituated between the rim l2 and the ring gear 14. Ring gear 14 includesteeth 16 which mesh with a drive pinion not shown. The regenerator core10 is adapted to rotate about its geometric axis 18 as the ring gear 14is driven. The regenerator seals are situated in sealing engagement withboth axial sides 20 and 22 of the regenerator core although they are notillustrated in the drawings.

A portion of the engine housing is shown at 24 and a portion of aregenerator cover is shown at 26. The housing portion 24 and the coverportion 26 are provided with aligned openings 28 and 30 respectively,for receiving adjusting bolt 32. Bolt 32 includes a head 34 which islocated near the interior of the regenerator cavity in the enginehousing and a threaded portion 36 on which is positioned an adjustingnut 38. A hollow shaft 40 surrounds the bolt 32. A first compressionspring 42 is situated between the regenerator cover portion 26 and theleft hand end of the hollow shaft 40. A second compression spring issituated between the right hand end of the hollow shaft 40 and a spacer44 slidably situated within the opening 28. The spacer 44 surrounds thestem of the bolt 40 and engages the nut 38.

The hollow shaft is formed with a pair of stems 46 and 48. A bearingwheel 50 is joumaled on the stem 46 and is held fast by suitablefastening means such as clips 52 and 54. A wear resistant, low frictionsleeve 56 surrounds the bearing wheel 50. It engages the adjacent side58 of the ring gear 14. A second bearing wheel 60 is journaled on thestem 48 and, like the wheel 50, it includes a low friction sleeve 62which engages the adjacent side 64 of the ring gear 14. The sleeves 56and 62 may be formed of Teflon or some other similar low frictionmaterial. The distance between the stem may be fixed and the diameter ofthe bearings may be varied to suit the width of the ring gear that ischosen. The ring gear is guided between the two bearing wheels androtates between them.

The hollow shaft may be adjusted in a direction parallel to the axis 18by suitably adjusting the nut 38. This nut may be located externallythereby permitting adjustment without the necessity for disassemblingthe regenerator system. The compression of the springs is changed uponadjustment of the nut 38. Accordingly, the position of the regeneratorcore is controlled by the external adjustment. Several of the adjustingmechanisms illustrated in FIG. 1 may be provided at angularly spacedpositions around the regenerator core 10. Suitable adjustments in eachof them may be made to prevent misalignment of the regenerator core andto establish the proper clearances. Even wear due to loss of clearanceand excess leakage due to excessive clearance can be avoided by suitableadjusting the appropriate adjusting mechanism at any one or more of theangularly positions.

The embodiment of FIG. 2 is somewhat similar to the embodiment of FIG.1, but it includes only a single bearing roller. The elements of theFIG. 2 construction that have counterpart elements in the FIG. 1construction have been identified by the same reference numeralsalthough prime notations have been added. The mode of operation of theFIG. 2 construction is the same as that described with reference to FIG.1.

The stem 46', which extends from the hollow sleeve shaft 40 carries abearing roller 66. A low friction sleeve of Teflon or some similarbearing material surrounds the bearing roller 66 as indicated at 68. Theroller 66 is positioned within a peripheral groove 70 formed in ringgear 72, which is joined to regenerator rim 12 by resilient ring gearmounting material 74.

The diameter of the bearing roller 66 is selected to fit the width ofthe peripheral groove 70 in the ring gear. Adjustments of the nut 38cause the stem 46 to shift in one axial direction or another therebyappropriately positioning the ring gear and controlling the direction ofthe axis of rotation of the regenerator.

The FIG. 3 construction has features that are common to the FIGS. 1 and2 constructions. It includes, for example, an adjusting bolt 32'. Acompression spring 40' is situated between a roller 74 which correspondsto roller 66 of the FIG. 2 embodiment. Roller 74 is journaled on acollar 76 which surrounds the bolt 32'. Spring 40' and spring 42 on theopposite side of the roller engage the sides of the collar 76. A lowfriction material is applied to the outer periphery of the roller 74 andto each axial side thereof, as indicated at 78, 80 and 82. The peripheryof roller 74 engages the peripheral groove 84 formed in ring gear 86 ofthe regenerator indicated generally by reference character 10.

In FIG. 4 is shown another embodiment that employs two rollers similarto the rollers shown in FIG. 1. The elements of the FIG. 4 constructionthat have counterpart elements of the FIG. 1 construction have beenindicated by similar reference characters although double primenotations are added. The carrier for the rollers of the FIG. 4construction differ from the carrier stems 46 and 48 of the FIG. 1construction by their bifurcated ends. The carrier for roller 60", forexample, includes a fork member 84 having two legs 86 and 88 which arejoined by pin 90. The roller 60 is joumaled on the pin 90, and periphery68" engages the side of ring gear 14". The roller 50- is similarlycarried by fork 92. Each fork 84 and 92 is carried by a shaft thatcorresponds to the hollow sleeve shaft 40 of the FIG. 1 construction.

FIG. 5 shows a peripheral spring that surrounds the hub of a heatexchanger of the type described with reference to FIGS. 1-4. The springis circular and the ends are formed with projections of lateral grooves94. The opposite end is formed with projections or lateral grooves 96.The spring which is designated by reference character 98 is providedwith shaped bends 100 and 102 in alternating relationship. The springitself. which is more appropriately termed a mounting ring for the ringgear, may be formed of high strength alloy by a hot forming process. Theshape of the mounting ring in the fabricated condition prior to assemblyis shown in FIG. 5. The shape of the mounting ring after assembly aboutthe regenerator rim 104 and within the ring gear 106 is shown in FIG. 9.The ends may be joined together by a linking element 108 which is formedwith axially extending projections 110 which register with the groovesformed in the ends of the mounting ring strip, thereby locking the twoends together in a continuous ring.

FIG. 10 shows a mounting ring, a ring gear and a rim in similarrelationships. The ring gear may be provided with a drive flange guideor projection 112 and the mounting ring is formed with a projection 114which is folded around the flange 112 thereby locking the mounting ringto the ring gear. The curvature of the shaped bends 100 and 102 and thethickness of mounting ring are determined by the amount of stressnecessary to provide adequate deflection, to absorb the thermalexpansion of the ring gear and to provide adequate friction between thering gear and the heat exchanger rim to prevent slippage. The ring gear,the mounting ring and the rim may be assembled in a suitable assemblyfixture which will permit the sliding of the ring gear over the ringinto position and which will permit the mounting ring to be pressedwithin the annular opening that is available between the ring gear andthe regenerator um. I

In the embodiment of FIGS. 11, 12 and 13, there is shown, in addition tothe mounting ring and the formed bends, a so-called cushion 116 which issecured to one side of formed bends 102. One side of the formed bends isbetween the regenerator rim and the mounting ring. The rim, which isshown at 118, is formed with a peripheral groove 120 which receives amounting ring 98. The cushion material preferably is a glass fiber rein-'5 forced cellulose rubber or the like. Shock forces are absorbed by thecushion material to complement the cushioning action of the mountingring itself and also to resist axial shifting movement of theregenerator core during the operation so that the proper seal loading ofthe adjusting mechanism of FIGS. 1 through 4 may be maintained.

The embodiment of FIG. 14 shows a regenerator construction similar toFIGS. 11 through 13, but the cushion material 124, which is a polymer,is reinforced with windings, such as woven glass fibers or carbon fibersor a metal wire. The fibers or the metal wire are coated with a primerfor establishing a bond between the reinforcement and the polymer. Thereinforcement wire or fibers are identified in FIG. 14 by referencecharacter 122. Other elements of the construction of FIG. 14 areidentified by the same reference characters used in FIGS. 11 through 13for corresponding elements, but prime notations are added. i

The embodiment of FIG. 15 includes a spring metal reinforcement 122'.Like the reinforcementof FIG. 14, reinforcement 122' is wrapped aroundthe periphery of the core and the polymer is poured and formed aroundit. The other elements of the FIG. 15 construction that are common tothe FIG. 14 construction are identified by similar reference characters,but double prime notations are added.

Having thus described a preferred embodiment of my invention what Iclaim and desire to secure by United States Letters Patent is:

l. A regenerator assembly for a gas turbine engine comprising a rotaryregenerator core mounted within a gas turbine engine, said assemblycomprising a ceramic matrix adapted to conduct a counterflow of hot andcool gases under differential pressures, a matrix rim surrounding theregenerator matrix, a ring gear surrounding the rim, a means foryieldably mounting the ring gear concentrically around the rim, anadjustable member situated adjacent the ring gear and mounted onportions of said housing for shifting movement in a direction generallyparallel to the axis of rotation of said regenerator matrix, bearingmeans carried by the adjustable member for positioning said rim relativeto said adjustable member, means for yieldably maintaining saidadjustable member in its adjusted position whereby the axial position ofsaid regenerator matrix with respect to the engine housing and-thedirection of the axis of rotation of said matrix may be controlled.

2. The combination as set forth in claim 1 wherein: said adjustablemember comprises a sleeve, an adjusting bolt disposed within saidsleeve, means for yieldably positioning said sleeve on said bolt wherebyrelative displacement of said sleeve with respect to said bolt isopposed by a spring force, means for adjusting the position of said boltwith respect to said sleeve to establish a relative adjustmenttherebetween and said bearing means comprises at least one bearingcarried by said sleeve in rolling engagement with said ring gear therebyimparting to said ring gear a supporting force that locates the axialdisposition of said regenerator with respect to said housing.

3. The combination of claim 2 wherein said sleeve carries two bearingrollers, one roller being situated on either axial side of said ringgear in rolling engagement therewith.

4. The combination as set forth in claim 2 wherein: said ring gearcomprises a peripheral groove, a roller situated in said groove, theperipheral margin of said roller being adapted to engage the axial sideof said groove, said roller being carried by said sleeve shaft forrotation about an axis that is transverse of the axis of rotation ofsaid regenerator.

5. The combination as set forth in claim 1 whereas: said rim has aperipheral spring ring positioned about its periphery, said springfrictionally engaging the outer surface of said rim and the innersurface of the surrounding ring gear whereby the latter is frictionallyand yieldably connected to said rim, said spring being in the form of astrip having alternately formed sections that apply radial forces tosaid rim and to said ring gear to establish a frictional drivingconnection therebetween.

6. The combination as set forth in claim 2 wherein: said rim has aperipheral spring ring positioned about its periphery, said springfrictionally engaging the outer surface of said rim and the innersurface of the surrounding ring gear whereby the latter is frictionallyand yieldably connected to said n'm, said spring being in the form of astrip having alternately formed sections that apply radial forces tosaid rim and to said ring gear to establish a frictional drivingconnection therebetween.

8. The combination as set forth in claim 4 wherein: said rim has aperipheral spring ring positioned about its periphery, said springfrictionally engaging the outer surface of said rim and the innersurface of the surrounding ring gear whereby the latter is frictionallyand yieldablyconnectedto said rim, said spring being in the form of astrip having alternately formed sections that apply radial forces tosaid rim and to said ring gear to establish a frictional drivingconnection therebetween.

9. The combination as set forth in claim 5 wherein: a yieldable heatresisting cushion is located between said spring and said regeneratorrim whereby forces distributed between said ring gear and said rim arecushioned thereby avoiding undesirable shock loads and maintaining theadjusted position established by adjusting said adjustable member.

10. The combination as set forth in claim 6 wherein: a yieldable heatresisting cushion is located between said spring and said regeneratorrim whereby forces distributed between said ring gear and said rim arecushioned thereby avoiding undesirable shock loads and maintaining theadjusted position established by adjusting said adjustable member.

11. The combination as set forth in claim 7 wherein: a yieldable heatresisting cushion is located between said spring and said regeneratorrim whereby forces distributed between said ring gear and said rim arecushioned thereby avoiding undesirable shock loads distributed betweensaid ring gear and said rim are cushioned thereby avoiding undesirableshock loads and maintaining the adjusted position established byadjusting said adjustable member.

UNITED STATES PATENT OFFICE r CERTIFICATE OF CORRECTION PATENT NO. 3,8u8,66 DATED 7: November 19, 197A INVENTOR(S) V- Dur'ga Nageswar' RaoIt is certified that error appears in the above-identified patent andthat said Letters Patent are hereby corrected as shown below: I

Column l line 2 1, canc el "hub" and substitute -1"im--,

Signed and sealed this 1st day of July 1.975.

(SEAL) Attest C. ILXRSHALL DANN Commissioner of Patents and TrademarksRUTH C. I-IA5ON Attesting Officer

1. A regenerator assembly for a gas turbine engine comprising a rotaryregenerator core mounted within a gas turbine engine, said assemblycomprising a ceramic matrix adapted to conduct a counterflow of hot andcool gases under differential pressures, a matrix rim surrounding theregenerator matrix, a ring gear surrounding the rim, a means foryieldably mounting the ring gear concentrically around the rim, anadjustable member situated adjacent the ring gear and mounted onportions of said housing for shifting movement in a direction generallyparallel to the axis of rotation of said regenerator matrix, bearingmeans carried by the adjustable member for positioning said rim relativeto said adjustable member, means for yieldably maintaining saidadjustable member in its adjusted position whereby the axial position ofsaid regenerator matrix with respect to the engine housing and thedirection of the axis of rotation of said matrix may be controlled. 2.The combination as set forth in claim 1 wherein: said adjustable membercomprises a sleeve, an adjusting bolt disposed within said sleeve, meansfor yieldably positioning said sleeve on said bolt whereby relativedisplacement of said sleeve with respect to said bolt is opposed by aspring force, means for adjusting the position of said bolt with respectto said sleeve to establish a relative adjustment therebetween and saidbearing means comprises at least one bearing carried by said sleeve inrolling engagement with said ring gear thereby imparting to said ringgear a supporting force that locates the axial disposition of saidregenerator with respect to said housing.
 3. The combination of claim 2wherein said sleeve carries two bearing rollers, one roller beingsituated on either axial side of said ring gear in rolling engagementtherewith.
 4. The combination as set forth in claim 2 wherein: said ringgear comprises a peripheral groove, a roller situated in said groove,the peripheral margin of said roller being adapted to engage the axialside of said groove, said roller being carried by said sleeve shaft forrotation about an axis that is transverse of the axis of rotation ofsaid regenerator.
 5. The combination as set forth in claim 1 whereas:said rim has a peripheral spring ring positioned about its periphery,said spring frictionally engaging the outer surface of said rim and theinner surface of the surrounding ring gear whereby the latter isfrictionally and yieldably connected to said rim, said spring being inthe form of a strip having alternately formed sections that apply radialforces to said rim and to said ring gear to establish a frictionaldriving connection therebetween.
 6. The combination as set forth inclaim 2 wherein: said rim has a peripheral spring ring positioned aboutits periphery, said spring frictionally engaging the outer surface ofsaid rim and the inner surface of the surrounding ring gear whereby thelatter is frictionally and yieldably connected to said rim, said springbeing in the form of a strip having alternately formed sections thatapply radial forces to said rim and to said ring gear to establish africtional driving connection therebetween.
 7. The combination as setforth in claim 3 wherein: said rim has a peripheral spring ringpositioned about its periphery, said spring frictionally engaging theouter surface of said rim and the inner surface of the surrounding ringgear whereby the latter is frictionally and yieldably connected to saidrim, said spring being in the form of a strip having alternately formedsections that apply radial forces to said rim and to said ring gear toestablish a frictional driving connection therebetween.
 8. Thecombination as set forth in claim 4 wherein: said rim has a peripheralspring ring posItioned about its periphery, said spring frictionallyengaging the outer surface of said rim and the inner surface of thesurrounding ring gear whereby the latter is frictionally and yieldablyconnected to said rim, said spring being in the form of a strip havingalternately formed sections that apply radial forces to said rim and tosaid ring gear to establish a frictional driving connectiontherebetween.
 9. The combination as set forth in claim 5 wherein: ayieldable heat resisting cushion is located between said spring and saidregenerator rim whereby forces distributed between said ring gear andsaid rim are cushioned thereby avoiding undesirable shock loads andmaintaining the adjusted position established by adjusting saidadjustable member.
 10. The combination as set forth in claim 6 wherein:a yieldable heat resisting cushion is located between said spring andsaid regenerator rim whereby forces distributed between said ring gearand said rim are cushioned thereby avoiding undesirable shock loads andmaintaining the adjusted position established by adjusting saidadjustable member.
 11. The combination as set forth in claim 7 wherein:a yieldable heat resisting cushion is located between said spring andsaid regenerator rim whereby forces distributed between said ring gearand said rim are cushioned thereby avoiding undesirable shock loads andmaintaining the adjusted position established by adjusting saidadjustable member.
 12. The combination as set forth in claim 8 wherein:a yieldable heat resisting cushion is located between said spring andsaid regenerator rim whereby forces distributed between said ring gearand said rim are cushioned thereby avoiding undesirable shock loads andmaintaining the adjusted position established by adjusting saidadjustable member.